1. Field of the Invention
The present invention relates to methods for evaluating kidney function in felines and methods for diagnosing kidney disease in felines. The invention further relates to kits and communicating means useful in practicing methods of the invention.
2. Description of the Art
Feline kidney disease is the second leading cause of feline death. Possible causes of feline kidney disease include congenital disorders (a feline being born with one kidney or an impaired kidney), kidney infection (resulting from an untreated urethra blockage), decreased blood supply to renal arteries (caused by, for example, diabetes, renal blockage, tumors, or arterial collapse), toxic chemicals, glomerulonephritis, interstitial nephritis, feline leukemia virus infection, feline infectious peritonitis, high blood pressure and renal tumors.
Because the reserve capacity of a kidney is large, kidney disease can progress undetected for a long time, and by the time external signs of the disease are visible, 60% to 75% of the renal mass may already be lost.
Though feline kidney disease is progressive and fatal, early diagnosis can allow the disease to be effectively managed for some time. Thus, there remains a need for new methods for evaluating kidney function and methods for diagnosing kidney disease in felines.
Ghrelin is a peptide hormone produced by endocrine cells in the placenta, kidney, pituitary and hypothalamus and by epithelial cells lining the fundus of the stomach. Initially synthesized as a preprohormone, ghrelin is proteolytically processed to a 28-amino acid peptide.
Ghrelin stimulates growth hormone secretion and regulates energy balance. In rodents and humans, ghrelin increases hunger through activation of hypothalamic feeding centers. Ghrelin secretion is up-regulated under conditions of negative energy balance and down-regulated under conditions of positive energy balance. In humans, dogs and rodents, ghrelin blood levels are reported to increase as kidney function decreases. This is not unexpected as declining kidney function indicates low energy and thus a need for increased food intake. The increase in blood ghrelin levels in these species acts to enhance appetite and in turn, increases food ingestion.